The thermal [3+2] cycloaddition reaction of N-acyliminophenanthridinium betaines with various allenoates has been investigated. The reaction was operationally simple and proceeded smoothly under mild reaction conditions, providing a variety of aromatic tetracyclic heterocycles in moderate to excellent yields.

The enantioselective addition of phenylethynylzinc to aldehydes catalyzed by a series of cyclopropane-based amino alcohol ligands 7 was investigated. The reactions afforded chiral propargylic alcohols in high yields (up to 96%) and with excellent enantioselectivities (up to 98% ee) under mild conditions. Furthermore, studies on the structural relationship show that the matching of the chiral center configuration is crucial to obtain the high enantioselectivity.